Turkish coastguard crew was caught attacking a boat with about 40 asylum seekers on board this morning, according to witnesses on board a humanitarian rescue boat.

The incident, shows the Turkish coastguard vessel chasing the dinghy carrying 20 men, 15 children and five women, off the Greek island of Agathonisi around 8am.

According to the Malta-based Migrant Report, on board the Migrant Offshore Aid Station (MOAS) rescue vessel, the coast guard officials started hitting the migrant boat, apparently aiming to disable the engine.

First they started hitting with a paddle that was not very effective before turning to a three-metre mooring rope hook, according to witnesses on board.

They kept alternating between slamming the pole against the back end of the eight-metre dinghy and trying to puncture the engine or dislodge the fuel line.

In the process, at least one of the migrants, a 22-year-old Iranian woman who was sitting right next to the engine, was hit on the head.

"While this was taking place, a larger coastguard vessel started circling the migrants’ boat creating a dangerous wave intended to flood the engine, but could have also capsized the vessel," Migrant Report said.

The chase, which lasted about 40 minutes, continued well into Greek waters with the Turkish coastguard pulling back when they were about half a mile away from the shore of Agathonisi.

A crew from Channel 4 shot footage of the incident, to be screened this evening.

Six days ago, footage had also surfaced of another Turkish crew adopting similar tactics with another migrant boat off the coastal town of Dikili.

The incident comes as EU leaders meet in Brussels to decide on a controversial plan to return all irregular migrants arriving on the Greek islands to Turkey.